Method and apparatus for handling sheets

ABSTRACT

The herein method and apparatus is used in connection with a corrugator machine. Corrugator machines convert paper from a web roll into flat corrugated box blanks. Such corrugator machines have a number of sections for forming such box blanks, and the devices in these sections are driven in synchronism by a line shaft. In the herein apparatus the blanks discharged from the corrugator lengthwise are moved at right angles, then shingled and stacked. The velocity of each of the steps in handling the sheets is co-ordinated for a relative speed ratio between the right angle take off of the sheets, the shingling and stacking, and is co-ordinated with the speed of the corrugator machine, through the line shaft in such a manner that when the corrugator speed varies, then the right angle take off, the shingling and the stacking also varies, but the same relative speed ratios between the right angle take off conveyor, shingling or transfer conveyor, and stacking conveyor are preserved. The ratio adjustments are predicated on the basic equation of the speed of movement on the right angle take off which receives the blanks from the corrugator as follows: Vd (W/L) Vc (1-S) in which Vc is the speed of the corrugator in ft./min., Vd is the speed on the right angle take off, W is the width and L is the length of the blank, and S is the ratio of the shingle, namely, S O/W in which O is the overlap; and the basic equation for the speed of the transfer conveyor or shingling conveyor relatively to the right angle take off is Vt (W/L) Vc (1-St) IN WHICH Vt is the speed of the transfer or shingling conveyor in ft./min. and St is the ratio of the shingle on the transfer conveyor; and the basic equation for the speed of the stacker is Vs (W/L) Vc (1-Ss) IN WHICH Vs is the speed of the stacker conveyor in ft./min. and Ss is the ratio of the shingle on the stacker. A device is provided for adjusting the ratio of the respective conveyors to predetermine the speeds of the conveyors relatively to the speed of the corrugator in accordance with the width and length of the blanks. A connection is provided to the line shaft of the corrugator so as to automatically control the overall speed in accordance with the variation of speed of the corrugator but maintaining the predetermined relative ratios between the respective conveyors.

United States Patent Martin 1 51 Apr. 25, 1972 [54] METHOD AND APPARATUSFOR HANDLING SHEETS [72] Inventor:

Calif. 9461 l 221 Filed: May 27,1970

211 Appl.No.: 40,908

Primary Examiner-J. W. Wegbreit Attorney-George B. White 5 7 ABSTRACTThe herein method and apparatus is used in connection with a corrugatormachine. Corrugator machines convert paper from a web roll into flatcorrugated box blanks. Such corrugator machines have a number ofsections for forming such box blanks, and the devices in these sectionsare driven in synchronism by a line shaft. in the herein apparatus theblanks discharged from the corrugator lengthwise are moved at rightangles, then shingled and stacked. The velocity of each of the steps inhandling the sheets is co-ordinated for a relative speed ratio betweenthe right angle take off of the sheets, the shingling and stacking, andis co-ordinated with the speed of the corrugator machine, through theline shaft in such a manner that when the corrugator speed varies, thenthe right angle Merrill D. Martin, 2 Mail Court, Oakland,

take off, the shingling and the stacking also varies. but the samerelative speed ratios between the right angle take off conveyor,shingling or transfer conveyor, and stacking conveyor are preserved. Theratio adjustments are predicated on the basic equation of the speed ofmovement on the right angle take off which recieves the blanks from thecorrugator as follows:

in which V, is the speed of the corrugator in ft/min. V, is the speed onthe right angle take off. W is the width and L is the length of theblank. and S is the ratio of the shingle. namely. S=O/W in which 0 isthe overlap: and the basic equation for the speed of the transferconveyor or shingling conveyor relatively to the right angle takeoffisin which V, is the speed of the transfer or shingling conveyor in ft/minand S, is the ratio of the shingle on the transfer conveyor; and thebasic equation for the speed ofthe stacker is Vt= W/L) v.11 -s,

in which V,, is the speed of the stacker conveyor in ft/min and S, isthe ratio of the shingle on the stacker. A device is provided foradjusting the ratio of the respective conveyors to predetermine thespeeds of the conveyors relatively to the speed of the corrugator inaccordance with the width and length of the blanks. A connection isprovided to the line shaft of the corrugator so as to automaticallycontrol the overall speed in accordance with the variation of speed ofthe corrugator but maintaining the predetermined relative ratios betweenthe respective conveyors.

3 Claims, 5 Drawing Flgures METHOD AND APPARATUS FOR HANDLING SHEETSBACKGROUND OF THE INVENTION At present the stacking of blanks dischargedfrom a corrugator is handled manually and the cost of hiring andtraining employees, including reduced production and supervisoryexpense, is very high. The work at the discharge end of the corrugatoris so difficult that there is a great turnover of labor, sometimes theman at the corrugator delivery must be changed weekly. An object of theinvention is to provide an automatic system for receiving the blanksfrom the corrugator and then to stack the blanks properly. A furtherobject of the invention is to provide a method and apparatus wherebysocalled multiple-outs" can be mechanically stacked at the highestcorrugator speeds and with about the same efficiency as "one-outs.Namely, when the sheet in the corrugator is cut into several stripsdischarged simultaneously from the corrugator, then if they are of equalwidth they can be handled simultaneously, and if they are of differentwidth, then they can be handled separately in this system. A feature ofthe invention is that a single operator can handle the entire system andthe labor required is minimal, and by reason of the particulararrangement of a right angle take off, and the transfer device orconveyor and the stacker, the relative speed between these steps can bepre-determined and maintained although the overall operation iscontrolled by and conforms to the speed in the corrugator.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a perspective view of thearrangement of the double system of conveyors for handling the sheetsfrom the corrugator to stacking.

FIG. 2 is a somewhat diagrammatic side view of the intake side of theconveyor system.

FIG. 3 is a diagrammatic view illustrating the connection between thecorrugator line shaft and the individually adjustable fluid motor drivesfor the elements of the conveyor system.

FIG. 4 is a diagrammatic view illustrating another form of connectionbetween the corrugator line shaft and the fluid motors.

FIG. 5 is a diagrammatic view showing the connection between thecorrugator line shaft and electric motor drive for the respectiveconveyors.

DETAILED DESCRIPTION The delivery end I of the corrugator machine hasdischarging conveyors 2 and 3 respectively adjacent to the knives 4 and5, whereby the blanks cut by the knives are discharged from thecorrugator. As shown on the lower conveyor and stacking system 6, theblanks are discharged from the lower discharge conveyors 3 directly onto a right angle take off 7 whereby the sheets are advanced at rightangles widthwise on to a transfer conveyor 8 and to a stacker conveyor 9by which latter the blanks are stacked into stacks 11 on a conveyor [2.

The upper discharge conveyors 2 discharge the blanks lengthwise on to alongitudinal delivery conveyor 13 which in turn delivers the blanks onto a more distant right angle take off 14, which in turn delivers theblanks on to another transfer conveyor 16 which in turn properlyshingles and transfers the blanks on to another stacker conveyor 17 toform stacks on a pallet.

Each of these conveyors in this system is driven by separate drivingmeans. For instance, in FIG. 3 a fluid motor 18 drives the right angletake off 14; another fluid motor 19 drives the transfer conveyor orshingling conveyor 16 and a third fluid motor 2! drives the stackerconveyor 17.

The essence of the improvement is that there are three variable volumepumps 22 each connected to the respective fluid motors l8, l9 and 21whereby the individual relative speeds of the right angle take offconveyor, the transfer conveyor and the stacking conveyor can beadjusted to a predetermined ratio, but all three variable volume pumps22 are driven through a transmission 23 by the line shaft 24 of thecorrugator indicated in FIG. 3.

Another instance shown in FIG. 4, a variable speed electric motor 26 isinterconnected between the three variable volume pumps 22 heretoforedescribed and a tachometer control 27 for the electric motor 26, and thetachometer control is driven through the transmission 23 by thecorrugator line shaft 24.

In the example shown in FIG. 5, electric motors 28, 29 and 31respectively drive the right angle take off 7 transfer or shinglingconveyor 8 and stacking conveyor 9. The electric motors 28, 29 and 31are connected to a suitable ratio control 32, for instance of a rheostattype, and are ultimately controlled by the tachometer control 27 drivenby the corrugator line shaft 24 as heretofore described.

In each of the above illustrations an initial ratio of conveyor speedscan be adjusted and predetermined, and preserved constantly throughoutthe operation, although the overall speed of handling the sheets iscontrolled by the corrugator line shaft 24 and the corresponding speedof operation of the eorrugator.

The basic principle whereby the relative speeds are determined andadjusted is predicated on the basic equation of in which V, is the speedof advance on the right angle take off 7 or 14 respectively, Wis thewidth and L is the length of the blank, V, is the speed of thecorrugator and S is the ratio of the shingle, namely S W/O in which 0 isthe overlap. Shingle in this art means the partial overlap of theconsecutive sheets on one another and the ratio of the shingle is theratio between the distance of the overlap relatively to the entire widthof the blank. This shingle is determined by the speed of the transfer orshingling conveyor relatively to the speed of the right angle take off.If the speed of the right angle take off is lower than the rate ofdelivery of the blanks from the corrugator, then the blanks may beshingled initially on the right angle take off. If the speed of thetransfer conveyor 8 or 16 respectively is the same as the speed ofdelivery of the right angle take off, then there is no change or formingof a shingle on the transfer conveyors. Relative increase of the speedof the transfer conveyor will shorten the overlap and relative decreaseof the speed of the transfer conveyor will increase the overlap.

The stacker conveyors 9 and 17 in this illustration operate in themanner described in U.S. Pat. No. 3,32 l .202 issued on May 23, I967 toMerrill D. Martin. Accordingly the variation of the aforementioned basicequation can be used to determine the speed of the transfer conveyor andof the stacker conveyor, namely the basic equation for the speed of thetransfer conveyor is F M r) in which V, is the speed of the transferconveyor in ftlmin and S, is the ratio of the shingle on the transferconveyor, namely S=Wl0 in which 0 is the desired overlap to beestablished on the transfer conveyor; and the basic equation for therelative speed of the stacker is V, W/L V l-S,) in which V, is the speedof the stacker in ftlmin. and S, is the desired shingle on the stackerconveyor.

By the above equations the relative speeds of the conveyors can beadjusted in accordance with the ratio of width and length of the blankas well as the ratio of shingle desired. As heretofore described, oncethis ratio is established, the ratio of speeds remains constant althoughthe speed itself will change as controlled by the corrugator line shaft.

Each right angle take off conveyor is provided with power rollers 33,and also with a transverse series of back stops 34 resiliently mountedand balanced on a cross frame 36 which is adjustable longitudinallyalong the power rollers 33 to a distance corresponding to the length ofthe blanks discharged on to the power rollers 33. In this manner in caseof so-called multipleouts, namely where the knives cut several blanks ofequal width and discharge simultaneously several such blanks, the speedof the right angle take off rollers 33 can be so adjusted that eachsheet advances widthwise to the point where the adjacent sheetdischarged will land directly on top of the preceding one in sequence.This permits the sheets or blanks to be handled in groups or piles oftwo superimposed blanks when running "two-out or three superimposedblanks when running three-out," and so on.

In the usual operation the transfer conveyor or shingling conveyor drivespeed is set somewhat lower to establish the initial shingle between theblanks or between the groups of blanks. The belt conveyors of thestacking conveyor 9 are adjusted normally slightly faster than those onthe transfer conveyor so as to pull the lower blanks or sheets of eachpile somewhat faster than the upper blanks and thereby to form a moreuniform shingle between the individual sheets.

The controls are located in such manner that they are accessible to theoperator at substantially one location so that the operator can adjustthe relative speeds of the conveyors in the system according to thelength and width of the blanks or sheets handled quickly, thereafter thespeed adjustment to the corrugator is accomplished automatically.

In all the forms of the herein combination of drives and conveyors, thesheets or boards are delivered to the stacker at intervals predeterminedby the width of the sheet or board so that a proper shingle or overlapis established, whereby the sheets are maintained in proper order duringthe movement of the stacker. The surface velocity of the stacker inthese adjustments is less than the surface velocity of the continuousside delivery. The ratio of velocity is maintained, although the variousconveyors conform to variations of speed of the corrugator, forinstance, while the corrugator is slowed down while making splices ofweb rolls, or when wet paper is run through the corrugator, or whenextra large sheets are run.

in the corrugator the continuous sheet unrolled from the web roll isslit into width of the boxes to be made and then passed to the knives tobe cut to length, and then ejected or discharged from the corrugator.Hence the velocity of the corrugator is proportional to the number ofsheets cut to the desired length per minute. indicated by the formula off V /L, wherein fc is the frequency of cut. After the sheets are ejectedthe next important factor is the shingling or the ratio of the overlapto the width (W) of the sheet. Hence the dependence in the basicequations on the ratio of width (W) and length (L) of the sheets cut atthe velocity of the corrugator (V Expressed otherwise, the delivery fromthe corrugator runs at a speed of W/L V ft./min., and this is varied atthe consecutive conveying according to the ratio of the proper shingleor overlap l-S). The right angle delivery, the transfer conveyor and thestacker conveyor can be thus set each to a ratio of the corrugator speedaccording to the dimensions of the sheet and these ratios are maintainedat all speeds of the corrugator by the method and device hereindescribed.

lclaim: l. in a method of stacking sheets delivered from the dischargeconveyor of a sheet making machine, the steps of conveyance of thesheets from the discharge conveyor to a stacker, varying the directionand speed of conveyance at a predetermined ratio to cause the sheets tooverlap consecutively at a predetermined ratio to the width of thesheets, and controlling the velocity of the movement of the sheets inaccordance with the velocity of said sheet making machine and the lengthand width of the cut sheet, and maintaining the said predeterminedvelocity ratio, said conveyance of said sheets from the sheet makingmachine to the stacker including, moving the sheet on a deliveryconveyor lengthwise, discharging the sheets from said delivery conveyorto a take-oft conveyor thereby to change the direction of movement ofsaid sheets to widthwise direction, discharging the sheets widthwise toa transfer conveyor at a different relative velocity, transferring saidsheets from said transfer conveyor to a stacker conveyor widthwise at adifferent velocity, the relative velocities of said conveyorspredetermining the spacing and overlap of the consecutive sheets on thestacker conveyor, driving each of said conveyors at its ownpredetermined variable speed controlled in accordance with the lengthand width of the cut sheets and in accordance with the velocity of thesheet making machine, the relative velocity of movement of the sheetsfrom said machine to said stacker being determined by the followingbasic equation: V, W/L V, in which equation V is the speed of delivery,W is the width, L is the length of the sheet and V is the speed of thecorrugator in ft./min., modified by the ratio of the overlap forming theshingle. 2. The method specified in claim I, wherein the travel of thesheet during said conveyance passes through different areas of differentvelocities, and said ratio velocities being between said areas.

3. The method specified in claim I, said sheet making machine being acorrugator, and all of said conveying steps of said sheet beingcontrolled by the velocity of the sheets discharged from said corrugatorwithout changing said predetermined ratio of velocity in the differentareas of conveyance of said sheets to said stacker.

I t i i

1. In a method of stacking sheets delivered from the discharge conveyorof a sheet making machine, the steps of conveyance of the sheets fromthe discharge conveyor to a stacker, varying the direction and speed ofconveyance at a predetermined ratio to cause the sheets to overlapconsecutively at a predetermined ratio to the width of the sheets, andcontrolling the velocity of the movement of the sheets in accordancewith the velocity of said sheet making machine and the length and widthof the cut sheet, and maintaining the said predetermined velocity ratio,said conveyance of said sheets from the sheet making machine to thestacker including, moving the sheet on a delivery conveyor lengthwise,discharging the sheets from said delivery conveyor to a take-offconveyor thereby to change the direction of movement of said sheets towidthwise direction, discharging the sheets widthwise to a transferconveyor at a different relative velocity, transferring said sheets fromsaid transfer conveyor to a stacker conveyor widthwise at a differentvelocity, the relative velocities of said conveyors predetermining thespacing and overlap of the consecutive sheets on the stacker conveyor,driving each of said conveyors at its own predetermined variable speedcontrolled in accordance with the length and width of the cut sheets andin accordance with the velocity of the sheet making machine, therelative velocity of movement of the sheets from said machine to saidstacker being determined by the following basic equation: Vd W/L Vc inwhich equation Vd is the speed of delivery, W is the width, L is thelength of the sheet and Vc is the speed of the corrugator in ft./min.,modified by the ratio of the overlap forming the shingle.
 2. The methodspecified in claim 1, wherein the travel of the sheet during saidconveyance passes through different areas of different velocities, andsaid ratio velocities being between said areas.
 3. The method specifiedin claim 1, said sheet making machine being a corrugator, and all ofsaid conveying steps of said sheet being controlled by the velocity ofthe sheets discharged from said corrugator without changing saidpredetermined ratio of velocity in the different areas of conveyance ofsaid sheets to said stacker.